Physician Assistant Chris Clough listens to testimony at his disciplinary hearing before the Board of Medicine in March, 2015. Brian Wallstin, NHPR

A New Hampshire physician's assistant was arrested Friday by federal agents on allegations he received kickbacks for prescribing large amounts of an opioid painkiller. According to officials, Clough was the state's top prescriber of a fentanyl spray called Subsys.

The Acting U.S. Attorney for New Hampshire says Clough wrote those prescriptions because he received cash payments from the drug's manufacturer, Insys. Insys allegedly paid Clough more than $41,000 for attending sham speaking gigs. Clough is charged with conspiracy and receiving kickbacks. He was ordered to permanently surrender his license in late 2016.

Clough will have his day in court, but the arrest is part of a broader federal investigation into Insys, which is charged with engaging in parallel kickback schemes with prescribers across the country.